Blade system for fans for industrial use

Described herein is a blade system (10) for fans for industrial use, comprising: -a blade (12), which extends longitudinally along a first reference axis (K) and defines within it a cavity (12A), wherein said blade has a cross section with flattened profile and is oriented with a major dimension (L1) along a second reference axis (H); and-a supporting unit (14), on which said blade (12) is fixed and which is inserted within the cavity (12A) of said blade, said supporting unit (14) being designed to be connected to the rotor (2) of a fan. The system is characterized in that: said cavity (12A) of said blade (12) has a cylindrical conformation and a cross section with flattened profile and is oriented with its major dimension (L2) along said second reference axis (H); and said supporting unit (14) comprises a tubular bar (16), which has a cross section with flattened profile and is oriented with a major dimension (L3) along said second reference axis (H), or else a first tubular bar (26A) and a second tubular bar (26C) with circular cross section, which are arranged alongside one another along said second reference axis (H).